Transformer



Dec. 20, 1927. 1,653,504

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Patented Dec. 20, 1927.

ERNST MOXTER, OF ST. LOUIS, MISSOURI.

PATENT OFFICE.

TRANSFORMER.

Application filed November 22, 1923. Serial No. 676,405.

This invention relates generally to electrical appliances and, more particularly, to a certain new and useful improvement in electrical appliances of the type generally known as transformers.

My present invention has for its chief object the provision of a transformer so constructed that variation in the intensity of the induced or secondary current may be selectively. effected independently of any change or variation in the voltage of the primary current and independently also of any variation or change in the structural factors and ratio of both the primary and F secondary windings.

With the above and other objectsin view, my present-invention resides in the provision or creation in the core of the transformer and intermediate the primary and secondary windings of a flux-affecting air or magnetic gap, whose dimensions are adjustable under the will and control of the operator, the reluctance of the gap, in turn, effecting a selected variation in the-intensity of the induced current, and in the novel features of form, construction, arrangement, and combination of parts hereinafter described and pointed out in the claims.

in the accompanying drawings,-

Figures 1 and 2 are plan and elevational views, respectively, of the transformer in circuit with service-wires and translating devices.

Referring now more in detail and by reference characters to the accompanying drawings, which illustrate a preferred form of the transformer, the transformer proper comprises, as is usual, a suitable preferably laminated iron core A, a primary or highvoltage winding B, and a secondary or lowvoltage winding C, the turns of the windings B and C being of suitable or desired number and ratio. In the present transformer, however, for purposes shortly appearing, the core A includes a pair of complementing oppositely disposed substantially U-shaped members 1, 2, upon the respective bights or yolres of which the primary and secondary windings B and G are suitably built up and disposed.

3 designates a suitable table or support of non-magnetic or insulation material, upon which the core-member 2 carrying the secondary winding G is attached as by straps t for slidable movement longitudinally of its bight. Upstanding from an end, and forming substantially a part, of table 3, is an approximately inverted L-shaped post or standard 4, -to which the core-member 1 carrying the primary winding B is attached and fixed as by screws 5.

Suitably mounted for axial rotary movement in a support or bearing 6 upstanding from the opposite end of table 3, is a screwmember 7 provided at one end with an operating or actuating member preferably in the form of a hand-wheel 8 and having threaded engagement at its opposite end, as shown, with a preferably non-magnetic or insulation block 9 suitably fastened to, and projecting laterally from, one of the projecting limbs of the movable core-member 2.

As is well known, if an alternating volt.- age is impressed on the primary winding B, an alternating current will be impelled in the winding, which will produce an alternating flux in the core A. An electromotiveforce will thereby be induced in the secondary winding C. The secondary circuit being closed, then such electromotive force will impel a current in the secondary circuit, the normal intensity of which is governed by the structural factors of the core A and of the windings B and G.

lit is also well known that the reluctance of air to the flow of magnetic flux is greater than that of iron. Utilizing this principle, I divide the core A, as described, into the separate co-operatingv members. 1 and 2, one of which, in the present instance the member 2 carrying the secondary winding C, is movable relatively to the other core-member 1 supporting the primary winding B.

Normally, as it may be said, as when the core-members 1 and 2 are in the respective positions shown in full lines in Figure 1, the projecting limbs thereof are substantially in touching or contacting engagement at their ends and the core A is substantially continuous and closed, when the transformer as a whole will function normally as a standard or ordinary transformer. However, on operation of the hand-wheel 8 in one direction, the core-member 2 and its carried winding C will be slidably moved on table 3 longitudinally of its bight and laterally or endwise relatively to the core-member 1 and the projecting limbs of core member 2 thereby adjustably shifted out of such normal touching or contacting engagement with the projecting limbs of the fixed core-member 1. By such movement, the continuity of the core A is broken or interrupted by an air or magnetic gap of adjustable dimensions depending within the will of the operator upon the amount of turning movement of hand-wheel 8 and the consequent slidable movement of the core-member 2. The magnetism created in the core is consequently weakened and the intensity of the induced current correspondingly reduced by the resistance or reluctance presented by the air ormagnetic gap so created in the core A of the transformer, the greater the air or magnetic gap so cut into the core the greater reduction or variation in the intensity of the induced current. On the core-member. 2 being reversely moved in returning to normal position, such air or magnetic gap is gradually reduced or cut-out and the induced current gradually or adjustably increased to full normal intensity.

Thus, without the employment of resist ance wires or devices and without special change in the structural factors of the transformer windings, I am enabled by adjustably interrupting the core A-of the transformer, to conveniently and efficiently effect vari ation in the intensity of the induced current to meet the requirements of the installation or particular translating devices or appliances. 1

In the drawing, I have illustrated my new so called variable current transformer in circuit with a preferred form of switch or contact mechanism. In these views, similarly, A designates the core comprising the relatively movable or shiftable sections or members 1, 2, B the primary winding, O the secondary winding, 3 the table or support, and 7 the rotary screw-member havin actuating engagement through the block 9 with the movable core-member 2. Leading from a suitable source of supply and having electrical connection with brushes 24, 24:, carried by the block 9, are the line-wires or mains 25, 25; and also carried by the block 9 and insulated from the brushes 24, are bridge-contacts 26, 26. Suitably fixed upon the table 3, is a pair of spaced preferably 'L-shaped contacts 27-27 continuously or permanently, as it may be said, in electrical connection through wires 2828 with the particular translating devices 29. Also suitably fixed upon table 3 in spaced relation forwardly from contacts 27, is a second pair of contacts 3030 also continuously or permanently, as it may be said, in electrical connection through wires 31-31 with the primary winding B. Also suitably fixed on table 3 in spaced relation rearwardly of the contacts 27, is a third pair of contacts 3232 continuously or permanently in electrical connection by means of wires 3333 with the secondary winding C of the transformer.

Normally, the transformer parts are in the 9, the brushes 24 are first carried into eiec trical engagement with the fixed contacts '27, when the translating devices 29 will be in direct circuit with the mains 25. On continued actuation of the screw-member 7, the brushes 24 will be moved out of electrical engagement with the contacts 27 and into electrical engagement with the fixed contacts 30 and, at the same time, the bridgemembers 26 will electricall contact with both the fixed contacts 27 an 32, whereupon the circuit is completed from the line-wires or mains 25 through the brushes 24, contacts 30, add wires 31 to the transformer winding B, and then from winding C through wires 33, contacts 32, bridge-members 26, contacts 27, and wires 28 to and through the translating devices 29, the intensity of the secondary current being selectively controlled by further actuation of the screw-member 7 as before described, until screw-member 7 has been actuated to its full rearward position, when the brushes 24 are out of engagement with the contacts 30 and the circuit to the translating devices 29 broken. On screwmember 7 being reversely or forwardly actuated, the circuit to and through the translating devices is completed reversely as here set forth.

My new transformer readily operates on load whether heavy or light and in accordance with the capacity of the coils and, as will be evident, may be advantageously emg ployed in many uses and installations and in bot step-down or step-up conditions.

I am aware that changes in the form, construction, arrangement, and combination of the several parts of the transformer may be made and substituted for those herein shown and described without departing from the nature and principle of my invention.

Having thus-described my invention, what I claim and desireto secure by Letters Patent is:

1. In combination, a source of electrical energy, a transformer including a core and primary and secondary windings disposed upon the core, translating devlces, means for interrupting the transformer-core for creating a magnetic gap intermediate the primary and secondary windings for affecting the intensity of the induced current, and means comprising a plurality of co-operating fixed and movable contacts for establishing electrical connection, on movement of said core interrupting-means, either directly between the source of electrical energy and the translating devices or between the source of electrical energy and the translating devices through the windings of the transformer.

2. In combination, a source of electrical energy, a transformer including a core comprising relatively movable sections, a primary winding disposed upon one of the sections, and a secondary winding disposed upon the other of said sections, translating devices, means for shifting one of said sections and its carried winding relatively to the other section and winding for creating a magnetic gap intermediate the primary and secondary windings for affecting the intensity of the induced current, and means including a plurality of co-operating fixed and movable contacts for establishing electrical connection, on movement of said core shifting-means, either directly between the source of electrical energy and the translating devices or between the source of electrical energy and the translating devices through the transformer.

In testimony whereof, I have signed my name to this specification.

ERNST MOXTER, 

